Studies on genotype-environment interaction (GxE) in half-sib progenies of cashew (Anacardium occidentale L.) in Tanzania

Abstract

The aim of the work was to provide information on the variability in performance of cashew over different geographic growing sites and on the potential to carry out effective selection. Half-sib progenies of 16 selected cashew clones (Anacardium occidentale L.) were used to establish progeny test trials at Kibiti and Chikomo. These sites were taken to represent cashew growing areas in north and south Tanzania respectively. Yield data and vegetative measurements recorded from 1989 to 1992 in both sites, were used to investigate the effect of site, progenies and their interaction. The performances of the progenies were compared in terms of their means and variances. There were differences in performance of the progenies in the two sites indicating the existence of genotype-environment interaction. The study identified progenies, which performed well at both sites, ones that performed badly at both and ones that varied in their performance. Thus it was possible to identify parents giving progenies which have wide adaptation under Tanzanian conditions. The data were used to calculate the heritability and response to selection for yield, canopy diameter, trunk cross sectional area and height. The heritabilities, and hence the response, of yield were low (3-40%) whereas that for height (47-72 %) suggested that it would be a character amenable to selection.

Keywords: cashew, genotype-environment interaction, progeny, yield, height, canopy diameter, trunk cross sectional area, heritability

Tanzania J. Agric. Sc. (1999) Vol. 2 No.1, 53-62